Treatment of whey



Patented Sept. 26, 1939 UNITED STATES PATENT oFFici:

TREATMENT OF WHEY No Drawing. Application December 18, 1936, Serial No.116,479

Claims.

This invention relates to the treatment ofwhey for the recovery of thecommercially usefullprod nets in it and tothe products resultingvtherefrom.

In the manufacture of cheese and industrial casein there remains theby-product-wheywhich contains practically all of the lactose originallypresent in the milk, a high proportion of the natural milk minerals,lactalbumin, and 10 certain other constituents normally present innatural milk. The whey, containing from 5 to 6 per cent of solid matter,is universally recognized as having food value of merit. In manyinstances the available whey from cheese factories desiccated for thepurpose of conservation and subsequently used as a food product.

In attempting to dry whey by the usual methods and apparatus used fordrying milk by the double roller process (known as the Just process anddescribed in Patent No. 712,545), certain diificulties are encountereddue to the inherent characof the drying cylinders. Raw or fluid whey hasan average composition substantially as follows:

Per cent Water 93.89

Solids 6.11 Protein matter 0.83 Lactose 4.55 Milk ash 0.72

Whey of this average composition becomes very viscous on the dryingcylinders as the water is evaporated from the surface of said cylindersas a consequence of the increasing concentration of milk sugar and otherconstituents. As the evaporation of water from the revolving cylindersis a continuous process the product becomes increasingly viscous as thewater is dispelled. This increasing viscosity in turn retards the rateof evaporation. Under various conditions of operation of the dryingapparatus it has been found and other establishments is disposed of inan' uneconomical manner which does not permit the- The inconteristics ofthe whey when subjected to the heat impracticable or even impossible toreduce the whey to awater free basis. The water remaining in the whey issuificient, in the presence of the heat of the cylinders, to hold themilk sugar in partial solution thus preventing a fully satisfactory andcomplete dehydration of the whey.

An object of this invention is to provide an improved method forhandling the whey whereby these difiiculties may be overcome. A furtherobject is to provide an improved method for recovering milk-sugar, watersoluble vitamin. for example, lactoflavin and other water solubleingredients of the whey. It is also an object of this invention toprovide a new I product from the treatment of whey. Other objects willbecome apparent.

In order to overcome the difl'lculties described above, I have foundthat if certain substances are added to the whey, it can be dried by thedouble roller process referred to above in a satisfactory 1 manner.These substances are added, from the theoretical standpoint, for thepurpose of introducing a number of minute interstices in the film ofwhey solids adhering to the drying cylinder during the final stages ofdesiccation. Such additions, made prior to applying the fluid whey tothe drying apparatus, permit a more rapid evaporation of water from thethin films which adhere to the revolving cylinders. Such substances alsochange the ash to lactose ratio from that of the normal whey and thusfacilitate drying, as will be described in greater detail. The additionof the substances, and in the manner to be mentioned hereinafter,creates in the viscous whey syrup him on the surface of the dryingcylinder, a porous condition which facilitates evaporation of the waterto a degree which permits complete or substantially complete drying ofthe mixture.

A specific example of my method involves the addition to 100 parts byweight of liquid whey, as derived from the manufacture of cheese orcasein for industrial purposes, or from other sources, from about 3 toas highas about 12 parts by weight of water insoluble organic matter ofa nitrogenous or carbonaceous nature or combinations of both these typesof products, For illustration a low grade flour, finely ground wheatmiddlings, soy bean meal, peanut meal and similar products may be addedto fluid whey and the mixture agitated to prevent settling orprecipitation of the suspended matter. The agitation of the mixture in asuitable tank or container is maintained during the application of saidmixture to the drying apparatus which may be the double rollerdesiccating apparatus referred to above operatedat atmospheric pressure.

The desiccating apparatus is operated under the usual conditionsprevailing during the drying of milk. For illustration, the dryingcylinders are heated with steam at an internal pressure which may varyfrom 50 to as high as 75 or pounds per square inch, with the speed 01'the rolls varying from as low as 6 to as high as'14 or 15 revolutionsper minute, respectively. Duringoperation in this manner that portion ofthe revolving, heated cylinder upon which the film is undergoing finaldesiccation reaches temperatures varying from 235 F. to 265 F. orthereabouts and in some instances may reach a temperature as high as 275F. immediately ahead of the knife edge which removes the desiccatedfilm. With the operation of the apparatus within the variations of steampressure, speed of rolls and roll surface temperature, as mentioned, ashigh as 800 to 1200 pounds of the fluid mixture may be applied to theapparatus per hour. -The resulting desiccated product, which is scrapedfrom the surface of the revolving cylinders in the same fashion as driedmilk is prepared, is completely dried or substantially so as it leavesthe drying cylinder. The dry film is readily pulverized by thesame,apparatus as used for pul verizing dry milk films; Such a productas just described resulting from the addition of 6% by weight of groundwheat middlings,'based upon the weight of the whey, has the followingcomposition: 4

This product will also contain other inherent conv stituents of the wheyand substances carried by the wheat middlings.

The process may also be carried out with whey which has been previouslyconcentrated before adding the suspended-ingredient and applying to thedouble roller drying apparatus. For illustration fluid whey irrespectiveof whether it is derived from cheese manufacture or from the productionof industrial caseins, or from some other sources, may be firstconcentrated in a vacuum pan, for example, at a temperature of about F.,or any other appropriate device, to a concentration as high as about 73per cent total solids; lower concentrations however are more appropriatefor practical handling. The concentrated whey, preferably used at aconcentration of from 35 to 50 per cent total solids, is heated in atank or receptacle provided with the proper agitator and facilities forheating the mixture. The temperature may be raised to .to F. and heldfor suflicient period of time to facilitate agitation and partial, orentire solution of such lac tose as may have previously crystallized. Itis immaterial whether all crystals of lactose are dissolved as long asthe concentrated material has a fluidity which permits thorough mixing.To this concentrated whey there is added, on the basis of the originalfluid whey solids, the carbonaceous or nitrogenousmaterial previouslymentioned, namely, wheat middlings, low grade -flour, soy bean meal orsimilar products.- From 3 or 4 to 12 pounds of said materials is addedper each 100 pounds of fluid whey equivalent wherein such fluid wheyequivalent is assumed to contain 6 per cent total solids or thereabouts.This mixture is thoroughly agitated .and maintained under agitationduring the time it is. being applied to the desiccating apparatus. Inemploying the concentrated whey with additions of extraneous material asdescribed the concentration of the whey-cereal mixture must bemaintained sufflciently low to permit a fluidity of the mixturesuch'that it will readily flow to the drying apparatus in the mannerusually provided.

Such a mixture may be completely desiccated, or substantially so, bycorrelation of operating conditions in regard to steam pressure andspeed of the rolls as previously mentioned for the drying ofunconcentrated whey and cereal mixtures.

In either case care should be taken not to subject the mixture to atemperature sufliciently high or for too long a time to totallygelatinize the starch.

application of additional dehydrating or desiceating procedures.

Products as mentioned above and which contain, on the dry basis, varyingproportions of whey solids and ground cereal grains obviously havevaluable food properties for stock and poultry feeding purposes. Suchmixtures are valuable as animalfoods when used alone or as an ingredientof animal rations. The fact is obvious that the addition of suchproducts to'whey which permit its desiccation and conservation byrelatively inexpensive methods and with standard desiccating equipment,permits an appreciable advancement in thepractical utilization andconservation of the food elements contained in the whey. The specificmethods and products as mentioned herein are not limited to thedesiccation of whey for-stock feeding purposes alone. The method mayalso be used for desiccating whey for human consumption wherein suchsubstances as.edible corn starch, or other similar cereal productssuitable for human consumption are used. Also, if desired, the watersoluble constituents of the dry powder may be separated by dissolvingthem in water.

The proportions of the added material to the whey solids may vary fromthe particular examples given. For example. the grain or cereal solidsmay be used in somewhat smaller proporderivatives may be used. Also,additional vitamins or vitamin-bearing substances may be added to theproducts described herein. For example, lactoflavin or any other flavinof the type generally known as lactoflavin but not restricted to thatrecovered from milk, may be added as a purified substance, as an impurec6ncentrate, or in the form of high lactofiavin-bearing products.Likewise, rice polish or other substances containing active vitaminsderived from rice polish or other suitable sources, as for example,wheat germ or wheat bran or the outer coating or aleurone layers, orgerms of these or other cereal grains, may be added to the whey productdried as described above. The resulting product is of high nutritivevalue. In this'way a product having a controlled or predeterminedvitamin potency, particularly of the water soluble vitamin of the 3- orG- complex, may be produced.

In anotherembodiment of my invention a wa- 76 ter insoluble, inorganicfiller may be added to the whey. For example, natural fluid whey asderived fromthe manufacture of cheese or industrial casein may .be driedwith the double cylinder drying apparatus referred to above by theaddition of inorganic material which serves Hie purpose of expeditingand facilitating the drying of the whey syrup film on the heated rollsin a manner'analogous to that mentioned in the above methods whereinnitrogenous or carbonaceous matter was added to the raw whey.

Diatomaceous earth, fullers earth, or clay of suitable characteristics,or ground chalk, are suitable for thepurpose when added to the fluidwhey in suitable proportion. For illustration, as little asapproximately 4 pounds of the diatomaceous earth (such as Filter-Gel) byweight per one hundred pounds of whey may be added. It is .desirable,from the standpoint of economy, to add as little of the inorganic filleras will permit proper desiccation and it is appreciated that larger.amounts than given in the illustration may be used without objectionfrom the standpoint. of the desiccation operation per se. The Filter-Cel or other inorganic material is added to the whey under. agitationandthe agitation maintained during application of the mixture to the dryingmachine. The following is typical of various runs wherein whey was driedby the addition of Filter-Gel:

Fluid whey used 6,492 lbs. I

Dry Flter-Cel used (approximately 4% by weight) 225 lbs. v

Continuous drying period about 6 hours.

Average weight of fluid mixture applied to the drying machine per hour1,118 lbs.

Internal steam pressure on drying cylinder 70-75 lbs. j

Whey solids in the fluid whey (according to analysis) 396 lbs.

Actual poundage of dry mixture recovered 632 lbs.

Mechanical loss of solids 16 lbs.

The dry product as removed from the desiccating cylinders by the knifeedge is not released as a continuous film as in the case of the solidsof milk or the whey cereal mixture previously mentioned, but rather thedesiccated product is removed as a dry powder or as irregularagglomerates slightly moist while hot at the instant of removal from thecylinder but which immediately dries in the air on cooling. The drynessof the powder released from the rolls depends upon the adjustment of therate at which. the fluid mixture is applied, the speed of the rolls andinternal steam pressure. In order to maintain a uniform character ofproduct as released by the knife uniform suspensions of the inorganicfiller and fluid whey should be maintained by appropriate agitation andby appropriate rate of. feeding the mixture to the drying machine. Therelative composition of raw whey and the desiccated product prepared asabove is shown by the following comparative analysis: a

. Raw whey Dry product arnaby concentrated whey may likewise be employedfor preparing the dry product with materials may also be usedin asimilar manner.

The product as prepared above may be used not only as an ingredient ofcertain stock or poultry rations, but may also be used as a source ofmilk sugar.

For the manufacture of milk sugar the dry 10 product prepared as in theabove examples is mixed with hot water, temperature about 160 to 180 F.,under agitation and for suflicient period of time to allow the sugar todissolve. The mixture is then simply filtered and condensed to thedesired degree. The use of this product for making milk sugar makes itunnecessary to carry out the preliminary treatment for the removal ofmilk albumin commonly employed in the usual processes for milk sugarmanufacture. The heat of the drying cylinders coagulates the albumin toa degree which permits it to be filtered out readily with thediatomaceous earth of Flter-Cel,

A determination of the protein content of whey previously treated andfiltered in the usual manner for the removal of albumin as usuallypracticed in the production of milk sugar showed a protein content of0.330 per cent. This percentage of protein in the albumin free whey maybe considered as a satisfactory standard. In order to ascertain whetherthe drying operation as described above was as effective inprecipitating coagulable protein and removing it from the whey followingdissolving and filtering. the pro- 5 tein content of such filtrate wasdetermined and found to be, as an average of several samples, 0.332 percent. By comparing this figure with the protein" content of whey treatedaccording to the commonpractice it is evident that the drying The motherliquor obtained after crystallization of the lactose may be used for therecovery of vitamins and other materials inherent in the whey butcompletely conserved as a result of the initial drying operation withthe inorganic filler. 5

because appropriate grades of diatomaceous earth or Filter-Gel have butlittle or at the most relatively slight absorptive properties for theretention of such vitamin materials, particularly lactoflavin.

The dry product may even be used direct as a means for recoveringvitamin materials inherent in the original whey, particularlylactoflavin. by treating the dry product without previous re moval ofthe lactose in accordance with appropriate methods or sequence ofmethods. such as that described in patent application Serial No.

61,890, filed February 1, 1936., "Concentration and isolation ofwater-soluble vitamins, Ansbacher. Supplee and Flanigan.

0 In another embodiment of my invention the 7 substance added may be aningredient of the whey, or certain ingredients soluble in the whey,whereby, for example, the ratio of protein to lactose or ash to lactosemay be varied The reason for unsatisfactory results in the drying ofnatural fluid whey on the double roller desiccating apparatus referredto is due primarily to the concentration of natural inorganic saltsfound in the whey. These salts are apparently melassigenic, or molassesforming in that they retard or prevent crystallization or finaldehydration of the milk sugar. The melassigenie character of certain ofthese natural milk minerals is further intensified at the relativelyhigh temperatures to which the product is subjected in using theatmospheric double drum dryer. The nitrogenous 'or protein content ofnatural whey appears to be a factor of only secondary importance. Theeffect of the protein of the particular character found in the whey isprimarily one of retarding rate of evaporation of the water in the wheysyrup film on the heated cylinders rather than inherent non-dryingproperties of the protein itself. Runs have been conducted which showthat when the protein to lactose or ash to lactose ratios are variedwithin certain limits by the addition of more lactose to the natural-whey than is normally contained therein, such mixture may be dried in asatisfactory and commercially practical manner by previously beenconcentrated to a total solidscontent of from to per cent, orthereabouts, before applying to the drying apparatus. Whey as derivedfrom the manufacture of cheese or from the manufacture of industrialcasein may be used wherein the inherent albumin remains in the whey orsuch whey may be used after removal of the albumin by heat coagulation.

In natural fluid whey or the solids thereof, the

I ratio of ash to lactose varies substantially within the range 1-6.2 to1-10.'7; within this range of ash to lactose ratios the protein tolactose ratio varies from 1-5.4 to 1-18.7, depending upon whether thewhey is derived from cheese manu- .facture or the manufacture ofindustrial casein,

and further depending upon whether the albumin has been removed from thewhey. Wheys with ash to lactose and concurrent protein'to lactose ratiosas mentioned above are not successfully dried to completion on thedouble roller apparatus. However, when lactose of either refined orsemi-refined grade is added to wheys of above character in an amountwhich substantially changes the ash to lactose ratio, successful dryingis accomplished.

Specific illustrations of this embodiment of the invention follow: Towhey derived from industrial casein manufacture there is added 6 lbs.o'flactose per hundred pounds of .whey. This mixture is concentrated ina vacuum pan to a pressure of 65 to lbs. on the cylinders revolving at aspeed of 4 to 6 revolutions per minute. Complete drying of the mixtureis accomplished resulting in removal of a dry product by the knife edge.The ratio of ash to lactose which permits this practical drying tocompletion is substantially 1-14.6.

Various other runs have been conducted wherein the ratios of am tolactose, brought about by the addition of appropriate amounts of lactoseto the fluid whey have been 1-14.9; 1-44.5; 1-15.8; 1-43.8. In all caseswhere the ash to lactose ratio was one to about fifteen or more,successful drying to completion was accomplished. The internal steampressure and the speed of revolutions of the drying cylinders was in allcases maintained between 65-80 lbs. and 4 6 revolutions per minute,respectively.

The concurrent ratio of protein to lactose in the various mixturesvaried from 1-15.6 to 1-101.. This evidence seems to indicate, inconfirmation of statements previously made herein,that the radio of ashto lactose is the primary condition determining whether successfuldrying to compleiion is accomplished. It is indicated that the criticalash to lactose ratio is in the neighborhood of 1-15; it is alsoindicated that the protein to lactose ratio may be variable and withoutsubstantial effect or importance, perrse, in determining degree andcompletion of drying.

Various embodiments have been included in this description asillustrative of my invention.

It is not intended, however, to restrict the invention to the particularillustrations given, it being apparent that variations may be made inutilizing it in varying degrees and under different circumstances. It isalso obvious that mixtures of two or more of the various substancesnamed may be added to the whey.

Also, particular reference has been made to the double-cylinder dryingapparatus (Just) in which the. milk or fluid mixture is subjected to atemperature of about 212 F. for about 2 or 3 minutes before forming thefilm on the revolving drum and while on the drum the film isprogressively subjected to temperatures of about 240 to 256 F. during aperiod of about 2 to 3 seconds, as a means and method for drying theproduct, but it is aparent that other processes and apparatus for dryingmay be used and it is not intended to restrict the invention to theparticular illustrative example. The terms used in describing theinvention have been used in their descriptive sense and not as terms oflimitation and it is intended that all equivalents thereof be includedwithin the scope of the appended claims.

I claim:

1. In 'the drying of whey by the drum process, the steps .of adding tothe whey an organic water-insoluble, nongelatinized substance of theclass consisting of grain middlings, grain flour,

soya bean meal, peanut meal and similar substances, agitating themixture to maintain the added substance in suspension and drying thewhey with the added substance by flowing the mixture in a fluidcondition upon -a drying cylinder andheating it thereon to a temperatureabove about 200 F.

2. In the drying of whey by the drum process,

the steps of adding to the whey 3 to 12%,

based on the weight of the whey, of a nongelatinized substance of theclass consisting of ground grain products, ground soya bean products andground peanut products, agitating the mixture, drying it by flowing itin a fluid condition upon pressure of about 50 to 80 pounds per squareinch and rotating at a speed of about 6 to 15 revolutions per minute andscraping the dried product from the cylinder.

3. In the drying of whey by the drum process, the steps of adding to thewhey 3 to 12%, based on the weight of the whey, of a nongelatinizedsubstance of the class consisting of ground grain products, ground soyabean products and ground peanut products, agitating the mixture, dryingit by flowing it in a fluid condition upon a drying cylinder heated tosuch a temperature and rotated at such a speed as to give a finaldesiccation temperature of about 235 to 275 F., and thereupon scrapingthe dried product from the cylinder.

4. In the recovery of milk products, the steps of adding to whey adiatomaceaus earth and desiccating the whey with the added diatomaceousearth byv flowing the mixture in a fluid 6. In the recovery of milkproducts, the steps of adding to whey a diatomaceous earth, desiccatingthewhey with the added diatomaceous earth, by flowing it in a fluidcondition upon a drying cylinder and heating it thereon to a temperatureabove about 200 F. and dissolving the water-soluble substances out ofthe dried mixture.

7. In the recovery of milk products, the steps of adding to whey adiatomaceous earth, desiceating the whey with the added diatomaceousearth, by flowing it in a fluid condition upon a drying cylinder andheating it thereon to a temperature above about 200 F., dissolving thewater-soluble substances out of the dried mixture and separating themilk sugar from the water solution.

8. In the recovery of milk products, the steps of adding to whey adiatomaceous earth, desiccating the whey with the added diatomaceousearth, by flowing it in a fluid condition upon a drying cylinder andheating it thereon to a temperature above about 200 F., dissolving thewa-.

tar-soluble substances out of the driedmixture and separatingtheiactoflavin iiro'm the-water solution.

9. In the recovery of adding to whey a water-insoluble, 'nongelatinized,anti-melassigenic, inorganic substance,

desiccating the whey with the added-substance of mm; products, thesteps.

by flowing it in a fluid condition upon a drying cylinder and heating itthereon to a temperature above about 200 F. and separating lactoflavinfrom the dried material.

10. In the recovery or milk products, the steps of. adding to whey awater-insoluble, nongelatinized, anti-melassigenic, inorganic substance,deslccating the whey with the added substance, by flowing it in a fluidcondition upon a drying cylinder and heating it thereon to a temperatureabove about 200 F., separating lactoflavin and dissolving water-solublesubstances from the dried mixture.

11. In the drying of whey by the drum process, the steps of adding tothe whey about 3 to 12%, based upon the weight of whey, of anon-gelforming, nongelatinized, water-insoluble', antimelassigenicsubstance and. desiccating the whey with the added substance by flowingit while fluid upon a drying cylinder and heating it to a temperatureabove about 200 F. on the drying cylinder.

12. In the drying of whey by the drum process,

the steps of adding-to the whey about 3 to 12%,

based upon the weight of whey, of a water-insoluble, non-gel-Iorming,nongelatinized, antimelassigenic substance adapted to increase theproportion of ash to the other ingredients of the whey and drying thewhey with the added sub stance by flowing themixture in a fluidcondition upon a drying cylinder and heating it to a temperature aboveabout 200 F. on the drying cylinder.

13. In the drying of whey by the drum process, the steps of adding tothe whey an organic, nongel-forming, nongelatinized, water-insoluble,anti-melassigenic substance: adapted to give porosity to the drying fllmand desiccating the whey with the added substance'bylflowhrg itin afluid condition upon a drying cylinder and subjecting it to atemperature above about 200 F. on the drying cylinder.

14. In the of whey by the drum process, the steps or adding to the wheyabout 3 to 12%, based upon the weight of whey, or an inorganic,nongelatinized, water-insoluble, anti-melassigenic substance anddesiccating the whey with the added substanceby flowing it in fluidcondition upon a drying cylinder and subjecting it thereon totemperatures above about 200 F.

i 15. In the drying of whey by the drum process, the steps or adding tothe whey a non-gel-torming, nongelatinized, water-insoluble substanceadapted to alter the proportions of ash to the other ingredients of thewhey-,.desiccating the whey with the added substance by flowing it ontoa drying cylinder and heating it'thereowto a temperature above about 200F. and dissolving the water-soluble substance out of the dried f owner:,0. BUPPLIE.

